Carb idle tuning

Discuss everything about Honda GoldWing. Feel free to ask any question related to GoldWing.

Moderators: CYBORG, Oldewing, robin1731, Forum Moderators

Post Reply
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Carb idle tuning

#1

Post by ericheath »

Question for suggestions from experts to novices like me. My idle has always been a little lumpy. I never could get it right.

I have always done the idle drop to open the screw until you get the highest rpm. I work my way around readjusting the main idle stop screw when done, but it's always a tad lumpy, not bad, but not like a good drum beat. I also have the quirk where if you rev it, it almost dies when it comes back to idle and then recovers. ( too rich, I think)

Today I tried to get the best idle beat. And I turned the idle screw in on number the three carb more than where it idled highest. It idled a little lower, but smoother and no bumble every now and then. It sounded better, beat wise. I adjusted the one carb a little also. To my surprise, not only did it sound better at idle, it dropped right to 1050 and didn't bog down. It might be significant that it was the three carb as that one is the base carb when synchronizing.

That worked for me. Maybe the veterans here have other tips as everyone is tweaking for summer.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
User avatar
Whiskerfish
President
President
Posts: 36850
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: Carb idle tuning

#2

Post by Whiskerfish »

Sounds to me like the # 3 was not pulling it's fair share at idle before you adjusted it. That would be why it would stumble when returning to idle.

I use the idle drop on all my carbs then I follow up with a Header temp check at idle. IR guns are cheap now like 30 bucks and can really provide some insight that synch and idle drop do not.
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: Carb idle tuning

#3

Post by ericheath »

Not sure what you mean by pulling its fair share, but I know a half turn out, and the idle rpm goes up. The idle pulse is even for about 15 out 16 pulses then a miss, repeat. What I thought--and I admit, I'm not used to it-- you know--thinking, anyways I think after syncing, and using highest rpm for the idle drop, it ends up too much fuel. Yes, it's the highest rpm, but when you turn the idle stop in to reach desired idle rpm, it's too rich.

I'm certain I read that if the idle falls on it's face for a moment after a throttle goose, it's a sign of too rich also. Mine used to drop to 5-600 for 1-2 seconds and then recover. These carbs make it more difficult to diagnose the rich factor due to the three circuits. Which circuit is too big? Pilot or primary?

Anyways, this is the first time I have ever had a nice even, pulse rhythm. No misses.

Today, I'll do a compression check after installing the new head.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
User avatar
wingrider
SUPER BIKER!!!!
SUPER BIKER!!!!
Posts: 3724
Joined: Thu May 24, 2012 12:15 pm
Location: Maple Lake, MN USA

Re: Carb idle tuning

#4

Post by wingrider »

Which bike are you playing with, and if It is the modified bike, Which carbs are you using?
2002 1800 Wing
2001 Valkyrie Interstate
1978 1200 EFI Wing with Motorvation Coupe Royale sidecar
1977 1200 Wing cafe/bobber project
1974 Suzuki GT550
User avatar
Whiskerfish
President
President
Posts: 36850
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: Carb idle tuning

#5

Post by Whiskerfish »

So Eric you are suggesting that # 3 was too rich at idle and by leaning it out you resolved your issue?

My experience with pristine carbs has been that at about 3/4 -1 turn open the jug begins to fire. I will usually go a good half turn out from there as my baseline then anywhere from 1-3 additional full turns out based on how the bike is setup and will be ridden.
Then check header temps and see if they are even close then ride it and do a plug check.
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: Carb idle tuning

#6

Post by ericheath »

Yes, leaning number three just a little got rid of the occasional hiccup. This is my Schizoid bike, 1200 block, 77 heads and cams, modified 77-764A carbs. Stock idle jet with 100 air jet, 62 primary with a 120 air jet, 130 main with 80 air jet, one washer under the needle. Slightly smaller hole in slide and cut-off valve. Checked compression this morning. 179-181 across the board.

My thinking is that you want the best idle, not necessarily the fastest idle at each adjuster. I don't recall a starting point for the idle drop, but my gut now tells me it should be three, then one, then two and four because three is the base for syncing. If you start at one of the others and then get to three, when you change it, you change the synch adjusters when you do. It shouldn't be much, but it could be enough to affect idle.

One thing I haven't liked is that when I let off the throttle hard, it is like putting on a brake. Scary in a curve at speed. I hope this helps. A little higher idle than the book also helps.

Once warmed up this morning it was perfect. Too bad I'm going to mess with another set sometime soon.
IMG_1566.JPG
IMG_1566.JPG (214.68 KiB) Viewed 135 times
Isn't it cute? Copying HOTT again. It's a good thing.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
User avatar
Whiskerfish
President
President
Posts: 36850
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: Carb idle tuning

#7

Post by Whiskerfish »

Yea with a Frankenstein setup like that it is impossible for me to figure out where I would start. But now that you have a setting on # 3 that you like is it worthwhile to try and setup the others the same?

I really do not think the order of doing idle settings makes a squat of a difference. Synch yes it makes perfect sense to match them to # 3 as the standard.
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Return to “GoldWing Tech Discussions”